This application relates generally to electro-optical sensors. More specifically, this application relates to electro-optical sensors for use in biometric analysis of optical spectra of tissue.
Biometric determination is generally defined as the process of measuring and using one or more physical or behavioral features or attributes to gain information about identity, age, or sex of a person, animal, or other biological entity. As well, in order to ensure security, the biometric determination task may include further tasks that ensure that the sample being measured is authentic and being measured on a living being. This latter test is referred to as a determination of liveness.
There are two common modes in which biometric determinations of identity occur: one-to-many (identification) and one-to-one (verification). One-to-many identification attempts to answer the question of, “do I know you?” The biometric measurement device collects a set of biometric data and from this information alone it assesses whether the person is a previously seen (“authorized”) individual. Systems that perform the one-to-many identification task, such as the FBI's Automatic Fingerprint Identification System (AFIS), are generally very expensive ($10 million or more) and require many minutes to detect a match between an unknown sample and a large database containing hundreds of thousands or millions of entries. The one-to-one mode of biometric analysis answers the question of, “are you who you say you are?” This mode is used in cases where an individual makes a claim of identity using a user name, a personal identification number (PIN) or other code, a magnetic card, or other means, and the device collects a set of biometric data which it uses to confirm the identity of the person. “Identification” will be used in this document to denote both identification and verification tasks.
Although in general the one-to-many identification task is more difficult than one-to-one, the two tasks become the same as the number of recognized or authorized users for a given biometric device decreases to just a single individual. Situations in which a biometric identification task has only a small number of entries in the authorization database are quite common. For example, biometric access to a residence, to a personal automobile, to a personal computer, to a cellular telephone, and to other such personal devices typically require an authorization database of just a few people.
Biometric identification and verification is useful in many applications. Examples include verifying identity prior to activating machinery or gaining entry to a secure area. Another example would be identification of an individual for matching that individual to records on file for that individual, such as for matching hospital patient records especially when the individual's identity is unknown. Biometric identification is also useful to match police records at the time a suspect is apprehended, but true identity of the suspect is not known. Additional uses of biometric identification or verification include automotive keyless start and entry applications, secure computer and network access applications, automated financial transaction applications, authorized handgun use applications, and time-and-attendance applications. In general, protected property will be the term used to describe all of the goods, places, services, and information that may require biometric authorization to access.
In addition to performing a biometric identification or verification and ensuring that the sample being measured is living tissue, there may also exist a need to determine an estimate of the age, sex, and other demographic characteristics of the person under test as part of the biometric determination task. For example, the U.S. Federal Trade Commission recently established a commission to examine the issue of remotely determining age of a person who is attempting to access a web site in order to block access by children to inappropriate sites. The Commission on Online Child Protection (COPA) heard testimony on Jun. 9, 2000 that indicated that then-known biometric techniques could not be used to aid the determination of a person's age based on any known biometric features.